var msgContent = document.querySelector(".msg-content");
// height:21.5rem; 展开
//height:9.5rem;收起
var detail = document.querySelector(".details");
var button = document.getElementById("open-close-button");
var isClose = true;
button.onclick = function(){
    if(isClose){
        //将详细信息展开
        button.setAttribute("class", "open-button");
        msgContent.style.height = "21.5rem";
        detail.style.display = "block";
    }
    else{
        //将详细信息关闭
        button.setAttribute("class", "close-button");
        msgContent.style.height="9.5rem";
        detail.style.display = "none";
    }
    isClose = !isClose;
}